The Netpage system involves the interaction between a user and a computer network (or stand alone computer) via a pen and paper based interface. The ‘pen’ is an electronic stylus with a marking or non-marking nib and an optical sensor for reading a pattern of coded data on the paper (or other surface).
The Netpage pen is an electronic stylus with force sensing, optical sensing and Bluetooth communication assemblies. A significant number of electronic components need to be housed within the pen casing together with a battery large enough to provide a useful battery life. Despite this, the overall dimensions of the pen need to be small enough for a user to manipulate it as they would a normal pen.
To sense a force applied to the nib of a Netpage pen, a force sensor can be mounted at the axially opposite end. With the force sensor axially aligned with the longitudinal axis nib, the contact force on the nib can be directly transferred to the load bearing surface of the force sensor. Force sensors, typically piezo-resistive, have a generally planar configuration with the load bearing member on one of the planar sides. Having the cartridge press directly onto the planar side of the force sensor requires it to be configured perpendicular to the longitudinal axis of the pen. However, it is much more convenient from a production point of view to mount the force sensor directly to the printed circuit board (PCB) of the pen. Electrically connecting the force sensor circuitry to the rest of the electronics is far easier if the force sensor contacts are simply placed onto the corresponding contacts on the PCB. To do this, the plane of the sensor needs to be parallel to the axis of the pen.